This invention pertains to sheet plastic devices for forming packages of a plurality of containers. More particularly, the invention relates to a multipackaging device and strip stock for producing such multipackaging devices for a predetermined number of generally cylindrical can-type containers disposed in two rows.
There are various forms of such multipackaging devices in the prior art. Most of these devices, which include those shown in U.S. Pat. Nos. 2,874,835--3,733,100--3,711,145--3,874,502 and 4,018,331, not only produced reliable packaging but were adapted for use with various relatively efficient carrier applicating machines and methods. Most of the known machines and methods for applying such plastic multipackaging devices to containers utilize a pair of laterally opposing jaws or jaw-like stretching members associated with each aperture in the device to carefully stretch and temporarily enlarge the aperture through the application of lateral stretching forces at spaced circumferential regions of the aperture so they may be snapped over the chimes of containers. Other methods and machines utilize pin-type members that move relative to and about a predetermined peripheral extent of the aperture and the chimes of a container to progressively snap the band creating the aperture about the periphery of and beneath the chimes of the individual containers.
A carrier device of the type generally described should include a series of bands which delineate the container receiving apertures and which create a package with the bands exerting sufficient compressive stress about the container so that the containers will not be inadvertently removed from the device but are still capable of selective removal from the device. Thus, the forces stretching the strip must cooperate with the carrier in such a manner as to provide the necessary holding force in the device without unduly stressing the carrier beyond its elastic limit at any given region.
While certain prior art carriers, methods and machines have proven to be commercially successful, it has been found that simpler methods may not utilize the controlled stretching of each aperture of the multipackaging device as discussed above. For example, in U.S. Pat. No. 4,018,331 a carrier device for three rows of containers is applied by a machine which stretches a carrier strip by application of forces solely at the outer margins of the three lane strip. The U.S. Pat. No. 4,018,331 carrier design incorporates a series of bands and webs creating apertures designed to be reconfigured to three lanes of lateraly aligned container receiving apertures due to the application of force to the outer margins of the laterally outermost rows. It is noted that this carrier and strip stock, since it is particularly designed for application to three or more rows of containers, will have the benefit of the inner lane of material to resist and react to the stretching forces.
In addition to the above noted use of two jaws on a strip of carrier stock for three or more lanes, it has also been suggested in U.S. application, Ser. No. 908,593, that a carrier strip for two or more lanes of containers may be applied thereto solely through the use of the cans themselves applying a lateral stretching force on the outer bands of the stock.